EP1395082A2 - Circuit magnétique pour haut-parleur avec bague de court-circuit - Google Patents

Circuit magnétique pour haut-parleur avec bague de court-circuit Download PDF

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Publication number
EP1395082A2
EP1395082A2 EP03254132A EP03254132A EP1395082A2 EP 1395082 A2 EP1395082 A2 EP 1395082A2 EP 03254132 A EP03254132 A EP 03254132A EP 03254132 A EP03254132 A EP 03254132A EP 1395082 A2 EP1395082 A2 EP 1395082A2
Authority
EP
European Patent Office
Prior art keywords
short
speaker
circuiting ring
voice coil
magnetic circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03254132A
Other languages
German (de)
English (en)
Other versions
EP1395082A3 (fr
Inventor
Kenta c/o Minebea Onkyo. Ltd Amino
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minebea Co Ltd
Original Assignee
Minebea Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minebea Co Ltd filed Critical Minebea Co Ltd
Publication of EP1395082A2 publication Critical patent/EP1395082A2/fr
Publication of EP1395082A3 publication Critical patent/EP1395082A3/fr
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/025—Magnetic circuit
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2209/00—Details of transducers of the moving-coil, moving-strip, or moving-wire type covered by H04R9/00 but not provided for in any of its subgroups
    • H04R2209/022—Aspects regarding the stray flux internal or external to the magnetic circuit, e.g. shielding, shape of magnetic circuit, flux compensation coils
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2400/00—Loudspeakers

Definitions

  • the present invention relates to a magnetic circuit for a speaker, especially a cone speaker for use in various audio equipment.
  • a short-circuiting ring disclosed in Japanese Patent No. 2737273 is made of a copper plate, formed into a cylinder, and attached to a center pole so as to be concentric with and parallel to a voice coil.
  • the short-circuiting ring is adapted to short an eddy current flowing in the center pole with a voice current flowing in the voice coil, thereby increasing the sound pressure level in a high frequency region.
  • Another short-circuiting ring is disclosed in Japanese Utility Model Publication No. Sho 63-29358, which has a slit formed in a longitudinal direction and is attached to a center pole, and still another short-circuiting ring is disclosed in Japanese Utility Model No. 2586414, which is composed of a meshwork comprising a plurality of electrically conductive thin wires meshed in a cylindrical form so as to be extendable, and which is attached to the side of the center pole except a gap portion.
  • the gap may possibly be expanded thereby reducing the magnetic flux density, and also the short-circuiting ring attached near the magnet has little influence on impedance in a high-frequency region, thus not producing much effect.
  • a speaker is disclosed in Japanese Patent Publication No. Hei 7-32514, in which no short-circuiting ring is used, and a magnet for a magnetic circuit is formed of an electrically conductive ferrite containing divalent iron. This, however, invites an increase in magnet cost, raising problems with practical use.
  • the present invention has been made in view of the above, and it is an object of the present invention to provide a magnetic circuit for a speaker, in which a short-circuiting ring is provided near a voice coil, thereby cutting off an AC magnetic field generated by the vibration of a voice coil so as to counteract an impedance in a high-frequency region to maintain sound pressure level.
  • a magnetic circuit for a speaker comprises: a bottom yoke having a center pole; a ring magnet; a top plate; and a cylindrical short-circuiting ring.
  • the short-circuiting ring is disposed close and parallel to and naturally concentric with a voice coil, and attached to the inner portion of the bottom of the top plate.
  • the short-circuiting ring has a height equal to or larger than the excursion (moving distance from the original position) of the voice coil.
  • the short-circuiting ring has a height equal to the distance from the bottom of the top plate to the top of the central portion of the bottom yoke.
  • the short-circuiting ring is made of aluminum or copper.
  • the center pole Due to the location of the short-circuiting ring, the AC magnetic field generated by the voice coil moving up and down can be effectively blocked off, thereby reducing significantly the current distortion, and also the short-circuiting ring does not restrict the magnetic gap, does not interfere with the movement of the voice coil, and can be attached simply and easily. Further, due to the length of the short-circuiting ring, the center pole has its circumference surface mostly covered, whereby the AC magnetic field beyond the excursion of the voice coil can be blocked off, the output sound pressure level in a high-frequency region can be increased, and at the same time the total harmonic distortion can be effectively suppressed.
  • a speaker 1 comprises: a magnetic circuit 7 which includes a bottom yoke 3 having a center pole 2 disposed at its central portion, a ring magnet 4 fixed onto the outer portion of the top face of the bottom yoke 3, and a top plate 5 fixed onto the top face of the magnet 4; a frame 9 fixed by screws onto the top face of the top plate 5; a spider 10 having its outer circumference fixed onto the lower part (toward the bottom) of the frame 9; a voice coil bobbin 11 suspended by the spider 10; a voice coil 12 wound around the voice coil bobbinll and movably disposed in a gap of the magnetic circuit 7; a cone diaphragm 13 fixed onto the upper part (toward the open top) of the frame 9 via a surround 14; and a dust cap 15 disposed over the voice coil bobbin 11.
  • a magnetic circuit 7 which includes a bottom yoke 3 having a center pole 2 disposed at its central portion, a ring magnet 4 fixed onto the outer portion of the top face of the bottom
  • the speaker 1 further includes: a cancel magnet 6 magnetized in a direction opposite to the magnet 4, disposed on the bottom face of the bottom yoke 3, and adapted to improve magnetic flux of the gap; and a yoke cover 8 adapted to prevent leakage flux from the magnetic circuit 7.
  • the magnetic circuit 7 further includes a short-circuiting ring 16 which is electrically conductive, has a height equal to or larger than the excursion of the voice coil 12, and which is disposed in an open space X defined by the lower face of the top plate 5, the inner circumferential face of the magnet 4, and the upper face of the bottom yoke 3.
  • the short-circuiting ring 16 is a hollow cylinder formed of aluminum, has a height substantially equal to the distance from the bottom face of the top plate 5 to the central portion of the top face of the bottom plate 3, has an inner diameter slightly larger than the outer diameter of the voice coil 12 so as to have its inner face located as close to the voice coil 12 as possible, and is disposed parallel to and naturally concentric with the voice coil 12.
  • the short-circuiting ring 16 can be fixed to the magnetic circuit 7, for example, such that the upper and lower ends of the short-circuiting ring 16 are provided with adhesive and attached to respective prescribed portions of the bottom face of the top plate 5 and the top face of the bottom yoke 3, but may alternatively be fixed, as shown in Figure 2, such that the upper and lower ends of the short-circuiting ring 16 with an increased height are fitted into respective circular grooves 17 corresponding to the short-circuiting ring 16 and located at the respective prescribed portions of the bottom face of the top plate 5 and the top face of the bottom yoke 3.
  • the short-circuiting ring 16 which is electrically conductive and has the height equal to or larger than the excursion of the voice coil 12
  • the short-circuiting ring 16 is attached to the bottom face of the top plate 5 so as to be disposed close and parallel to and naturally concentric with the voice coil 12
  • an AC magnetic field generated by the vibration of the voice coil 12 is blocked off by the short-circuiting ring 16, whereby the harmonic distortion can be reduced, and at the same time an impedance in a high-frequency region can be counteracted thus maintaining sound pressure.
  • a dynamic cone speaker with a magnetic circuit shown in Fig. 1 was produced.
  • the dynamic cone of the speaker has a diameter of 150 mm, and the short-circuiting ring is made of aluminum and has a length of 19 mm and a thickness of 2 mm, and the voice coil has an impedance of 4 ⁇ .
  • the admittance curve (impedance curve) and sound pressure frequency characteristics of this speaker are shown in Fig. 3, and the characteristics of the total harmonic distortion (THD), second harmonic distortion and third harmonic distortion are shown in Fig. 5.
  • a dynamic cone speaker which includes the same magnetic circuit as the working example speaker but excludes the short-circuiting ring, was produced.
  • the admittance curve (impedance curve) and sound pressure frequency characteristics of the speaker are shown in Fig. 4, and the characteristics of the total harmonic distortion (THD), second harmonic distortion and third harmonic distortion are shown in Fig. 6.
  • the solid line refers to admittance curve
  • the dotted line refers to frequency characteristics
  • the heavy solid line refers to total harmonic distortion (THD)
  • the dotted line refers to second harmonic distortion
  • the thin solid line refers to third harmonic distortion.
  • the working example speaker shows a slower decline in admittance curve than the comparative example speaker. This is attributable to it that in the working example, the short-circuiting ring generates back electromotive force thereby canceling out the magnetic flux generated by the voice current and causing short-circuit, whereby resistance value is decreased resulting in maintaining sound pressure from 1 kHz upward.
  • the second harmonic distortion large part of which magnetic distortion accounts for, is reduced from 100 Hz upward, and at the same time the third harmonic distortion is reduced, whereby the total harmonic distortion (THD) is significantly reduced, compared with the comparative example speaker.
  • the height of the short-circuiting ring 16 is equal to the distance from the bottom face of the top plate 5 to the central portion of the top face of the bottom yoke 3 so as to block off an AC magnetic field covering an area larger than the excursion of the voice coil 12, but may alternatively be larger than the excursion of the voice coil 12.
  • the upper and lower ends may respectively be provided with a plurality of protrusions arranged at a prescribed interval and the ends may engage with the grooves 17 by means of the protrusions.
  • the short-circuiting ring may be made of copper.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
EP03254132A 2002-08-28 2003-06-28 Circuit magnétique pour haut-parleur avec bague de court-circuit Withdrawn EP1395082A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2002248841A JP3752674B2 (ja) 2002-08-28 2002-08-28 スピーカ用磁気回路
JP2002248841 2002-08-28

Publications (2)

Publication Number Publication Date
EP1395082A2 true EP1395082A2 (fr) 2004-03-03
EP1395082A3 EP1395082A3 (fr) 2004-06-16

Family

ID=31492575

Family Applications (1)

Application Number Title Priority Date Filing Date
EP03254132A Withdrawn EP1395082A3 (fr) 2002-08-28 2003-06-28 Circuit magnétique pour haut-parleur avec bague de court-circuit

Country Status (3)

Country Link
US (1) US7031489B2 (fr)
EP (1) EP1395082A3 (fr)
JP (1) JP3752674B2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1802166A2 (fr) * 2005-12-26 2007-06-27 Pioneer Corporation Dispositif de haut-parleur
CN105491491A (zh) * 2016-01-26 2016-04-13 深圳市赛音微电子有限公司 扬声器及其磁铁组件

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3752674B2 (ja) * 2002-08-28 2006-03-08 ミネベア株式会社 スピーカ用磁気回路
JP2006261962A (ja) * 2005-03-16 2006-09-28 Pioneer Electronic Corp スピーカ装置
JP2007142981A (ja) * 2005-11-21 2007-06-07 Pioneer Electronic Corp スピーカ装置
US8270660B2 (en) * 2006-07-03 2012-09-18 Pioneer Corporation Speaker device and speaker unit
JP4620008B2 (ja) * 2006-07-28 2011-01-26 日本電産ピジョン株式会社 ボイスコイルの取り付け方法
US8139816B2 (en) * 2007-09-26 2012-03-20 Sentient Magnetics, Inc. Acoustic transducer
US20100054520A1 (en) * 2008-08-28 2010-03-04 Jason Myles Cobb Loudspeaker
US20100246880A1 (en) * 2009-03-30 2010-09-30 Oxford J Craig Method and apparatus for enhanced stimulation of the limbic auditory response
CN103797818B (zh) 2012-06-22 2015-04-29 松下电器产业株式会社 扬声器及使用该扬声器的电子设备、移动体装置以及扬声器的制造方法
CN203632854U (zh) * 2013-09-25 2014-06-04 瑞声科技(沭阳)有限公司 电声器件
CN106303855B (zh) * 2016-08-26 2020-01-24 迪芬尼香港有限公司 一种扬声器结构
DK180111B1 (en) * 2018-10-04 2020-05-06 Upper Level Aps A magnetic system for an electromechanical transducer
CN208821073U (zh) * 2018-10-15 2019-05-03 苏州上声电子股份有限公司 一种扬声器磁路系统及扬声器
FR3104364A1 (fr) * 2019-12-06 2021-06-11 Cabasse Haut-parleur à grande excursion, faible distorsion et faible profondeur

Citations (5)

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Publication number Priority date Publication date Assignee Title
US3881074A (en) * 1971-03-10 1975-04-29 Hitachi Ltd Electro-acoustic transducer
JPS5838099A (ja) * 1981-08-31 1983-03-05 Matsushita Electric Ind Co Ltd スピ−カ
JPS58206298A (ja) * 1982-05-27 1983-12-01 Mitsubishi Electric Corp スピ−カ用磁気回路
JPH03201797A (ja) * 1989-12-28 1991-09-03 Matsushita Electric Ind Co Ltd スピーカ
JPH07170597A (ja) * 1993-12-15 1995-07-04 Matsushita Electric Ind Co Ltd スピーカ

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US3803522A (en) * 1973-05-11 1974-04-09 Arnold Eng Co Air gap extending the width of a permanent magnet assembly
JPS6329358A (ja) 1986-07-22 1988-02-08 Hitachi Electronics Eng Co Ltd 磁気カ−ド処理方式
JP2737273B2 (ja) 1989-07-12 1998-04-08 松下電器産業株式会社 動電型スピーカ
JP3177758B2 (ja) * 1993-04-07 2001-06-18 ミネベア株式会社 スピーカおよびその製造方法
JP2586414B2 (ja) 1993-05-28 1997-02-26 アキレス株式会社 射出成形靴の製造方法
JPH0732514A (ja) 1993-07-20 1995-02-03 Toho Vinyl Kk 吊下げ包装袋及びその製造方法
US5734734A (en) * 1995-12-29 1998-03-31 Proni; Lucio Audio voice coil adaptor ring
US6768806B1 (en) * 1998-03-19 2004-07-27 Harman International Industries, Incorporated Shorting rings in dual-coil dual-gap loudspeaker drivers
US6774510B1 (en) * 2000-10-25 2004-08-10 Harman International Industries, Inc. Electromagnetic motor with flux stabilization ring, saturation tips, and radiator
US6639993B2 (en) * 2001-12-29 2003-10-28 Alpine Electronics, Inc Loudspeaker with low distortion and high output power
JP4073717B2 (ja) * 2002-06-19 2008-04-09 パイオニア株式会社 内磁型磁気回路及びスピーカ装置
JP3752674B2 (ja) * 2002-08-28 2006-03-08 ミネベア株式会社 スピーカ用磁気回路

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881074A (en) * 1971-03-10 1975-04-29 Hitachi Ltd Electro-acoustic transducer
JPS5838099A (ja) * 1981-08-31 1983-03-05 Matsushita Electric Ind Co Ltd スピ−カ
JPS58206298A (ja) * 1982-05-27 1983-12-01 Mitsubishi Electric Corp スピ−カ用磁気回路
JPH03201797A (ja) * 1989-12-28 1991-09-03 Matsushita Electric Ind Co Ltd スピーカ
JPH07170597A (ja) * 1993-12-15 1995-07-04 Matsushita Electric Ind Co Ltd スピーカ

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 007, no. 119 (E-177), 24 May 1983 (1983-05-24) & JP 58 038099 A (MATSUSHITA DENKI SANGYO KK), 5 March 1983 (1983-03-05) *
PATENT ABSTRACTS OF JAPAN vol. 008, no. 053 (E-231), 9 March 1984 (1984-03-09) & JP 58 206298 A (MITSUBISHI DENKI KK), 1 December 1983 (1983-12-01) *
PATENT ABSTRACTS OF JAPAN vol. 015, no. 465 (E-1138), 26 November 1991 (1991-11-26) & JP 03 201797 A (MATSUSHITA ELECTRIC IND CO LTD), 3 September 1991 (1991-09-03) *
PATENT ABSTRACTS OF JAPAN vol. 1995, no. 10, 30 November 1995 (1995-11-30) & JP 07 170597 A (MATSUSHITA ELECTRIC IND CO LTD), 4 July 1995 (1995-07-04) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1802166A2 (fr) * 2005-12-26 2007-06-27 Pioneer Corporation Dispositif de haut-parleur
EP1802166A3 (fr) * 2005-12-26 2007-08-08 Pioneer Corporation Dispositif de haut-parleur
CN105491491A (zh) * 2016-01-26 2016-04-13 深圳市赛音微电子有限公司 扬声器及其磁铁组件

Also Published As

Publication number Publication date
US20040042631A1 (en) 2004-03-04
JP2004088589A (ja) 2004-03-18
JP3752674B2 (ja) 2006-03-08
EP1395082A3 (fr) 2004-06-16
US7031489B2 (en) 2006-04-18

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